New England Patriots star wide receiver Julian Edelman appeared to injure himself during a drill at practice on Tuesday morning.

Both Edelman and linebacker Rob Ninkovich left practice early.

Phil Perry of Comcast Sports Net said that Edelman checked out of practice after participating in one-on-one drills. He slammed his helmet to the ground after talking to trainers. He then walked off the practice field after watching a few minutes of practice with the team’s trainer.

The receiver walked off the field under his own power, not needing a cart to take him off.